This invention relates to an ethylenic polymer foam structure having enhanced toughness and elasticity and a process for making the foam.
Commercially-available ethylenic polymer foam structures are typically made with conventional highly-branched low density polyethylene (LDPE) resins made by high pressure processes. Foam structures of LDPE resins have been found to be suitable for cushion packaging and other applications.
There exists a need for an ethylenic polymer foam structure having better toughness and elastic characteristics than foam structures of LDPE resins. Such tougher and more elastic foam structures would be very useful in sporting and leisure applications as well as cushion packaging applications.
One means of making a tougher, more elastic ethylenic polymer foam structure is to utilize conventional, heterogeneously-branched linear low density polyethylene (LLDPE) resins as the primary or secondary resin in the foam. Unfortunately, LLDPE resins have undesirable extrusion foaming characteristics.
It would be desirable to have an ethylenic polymer foam having foamability similar to LDPE foams and toughness and elasticity similar to LLDPE foams.